A hypnic headache is a type of headache that only occurs during sleep, usually at a consistent time. People may also refer to hypnic headaches as alarm clock headaches because they often cause individuals to wake.

According to research, hypnic headaches are rare — approximately 0.07% of people who visit a doctor about headaches have hypnic headaches. However, they can be frequent in those who experience them, with an average occurrence of 10 times per month. They usually start after the age of 50 years, but they may also affect younger people.

Keep reading to explore the symptoms, causes, and diagnosis of hypnic headaches. We also explore treatments and the outlook for this symptom.

Person with hypnic headacheShare on Pinterest

According to a 2021 research article, most people who report a hypnic headache describe it as dull, but the pain can also be pulsating or throbbing. While the pain is generally moderate to severe, some individuals experience mild discomfort. The headache can last from 15 minutes to 4 hours after waking.

According to the article, hypnic headaches:

  • affect adults of all sexes equally
  • usually affect both sides of the head
  • cause pain that typically lasts 30–60 minutes after waking up

People may also experience more than one hypnic headache per night.

In rare cases, individuals may also experience the following symptoms with hypnic headaches:

  • nausea
  • vomiting
  • extreme sensitivity to light
  • an uncharacteristic fear of sound

Experts do not precisely know what causes hypnic headaches, but it may have links with the following:

  • Pain management: Various parts of the brain play a role in pain management, so an issue with any of them can affect the perception of pain.
  • Melatonin production: The brain produces this hormone at night to induce sleep. As people get older, melatonin production declines.
  • Rapid eye movement (REM) sleep: This is a stage of sleep when the eyes move rapidly in different directions, while intense dreaming can occur. The onset of hypnic headaches has a link to REM sleep, which means there may be a connection between the headaches and the physiological effects that may occur during this sleep stage.

According to one source, hypnic headaches mostly affect postmenopausal females. However, researchers have yet to investigate the connection between menopause and hypnic headaches specifically.

A 2018 article suggests that hormonal changes during menopause could have a link to some types of headaches. Treatments, such as hormonal replacement therapy, may worsen migraine headaches. Some people may also notice an improvement or no change in headache symptoms during menopause.

However, hypnic headaches are not the same as migraine headaches. As a result, the study’s findings may not necessarily apply to hypnic headaches.

Doctors mostly base a hypnic headache diagnosis on a person’s headache patterns. This consists of the following factors:

  • if the headaches occur solely at night
  • duration of headaches
  • frequency of headaches

To diagnose a hypnic headache, healthcare professionals may need to rule out other causes of nighttime headaches, depending on associated symptoms. These include conditions, such as:

  • brain tumors, characteristic growths of cells in the brain
  • a brain aneurysm or other blood vessel abnormality in the brain
  • medication side effects
  • obstructive sleep apnea, a condition that momentarily stops breathing during sleep
  • giant cell arteritis, the inflammation of the lining in the arteries, which can occur in the temples

An MRI can rule out structural abnormalities, such as brain tumors. In addition, an overnight study that monitors body processes during sleep can rule out sleep apnea.

A brain MRI may also reveal a reduction in grey matter volume in a part of the brain called the hypothalamus, which is responsible for keeping the body in a balanced, stable condition. It also regulates daily rhythms, including the release of melatonin at nighttime.

The most common treatment for hypnic headaches is caffeine in the form of coffee at bedtime. In most people who experience these headaches, this does not hinder sleep.

The below medications may be effective in some cases:

  • melatonin
  • indomethacin (Indocin), a nonsteroidal anti-inflammatory drug
  • flunarizine (Abifluz), a calcium channel blocker that doctors may use to treat migraine headaches

Additionally, doctors may sometimes prescribe lithium carbonate (Lithobid), a medication for bipolar disorder. Due to the side effects, people need to use lithium carbonate with caution, particularly if they take diuretics or have any of the following:

  • kidney disease
  • thyroid disease
  • dehydration

Research suggests that approximately 17% of people with hypnic headaches go into remission over time, but most experience the condition over the long term. In 40% of individuals, treatment is effective in treating hypnic headaches.

A 2016 study also reports treatment can make a difference. Researchers examined the medical records of 40 people who had hypnic headaches between 2008–2014. They found lithium was the most effective treatment, followed by caffeine at bedtime.

Of the people who took lithium, 70% had a complete response and 20% had a moderate response. Among those who took caffeine at bedtime, 28% had a complete response and 43% had a moderate response. Individuals also experienced benefits from taking caffeine upon awakening with a headache.

A hypnic headache involves a dull pain on both sides of the head that causes a person to wake from sleep. It can last from 15 minutes to 4 hours and can recur at least 15 times per month.

To diagnose the condition, doctors will first rule out other possible causes of the headaches, such as obstructive sleep apnea. Healthcare professionals may use tests to monitor sleep or carry out MRI scans of the brain. They will also look at symptom patterns to make a diagnosis.

Treatment may involve drinking coffee at bedtime, which might not negatively impact sleep for people with hypnic headaches.

If caffeine is not effective, a doctor may prescribe medications, such as lithium (Lithobid) or indomethacin (Indocin). However, they can both cause side effects, so individuals may want to discuss these with a healthcare professional.

Treatments can be effective in treating hypnic headaches. Some people may experience complete remission, while others may have to manage the condition over the long term.